CN201166697Y - Power cable monitoring device - Google Patents
Power cable monitoring device Download PDFInfo
- Publication number
- CN201166697Y CN201166697Y CNU2007200618832U CN200720061883U CN201166697Y CN 201166697 Y CN201166697 Y CN 201166697Y CN U2007200618832 U CNU2007200618832 U CN U2007200618832U CN 200720061883 U CN200720061883 U CN 200720061883U CN 201166697 Y CN201166697 Y CN 201166697Y
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- cable
- power cable
- monitoring device
- transmitter
- transformer
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Abstract
The utility model provides a power cable monitoring device which can be used for monitoring the state of the power cable on a real-time basis. The power cable monitoring device comprises a transmitter and a receiver; the transmitter is used for transmitting a monitoring signal so that induced electromotive force can be generated in the conducting layer of the monitored cable protecting layer, the receiver is used for detecting the induced current generated by the induced electromotive force in the conducting layer loop and outputting the detection result, the transmitter is provided with a transmitting transformer sleeved on the power cable, a transmitting winding is used as the primary winding of the transmitting transformer, and the monitored cable is used as the secondary winding of the transmitting transformer. By utilizing the power cable monitoring device, the safety protection system for the power cable can be established, real-time monitoring and automatic alarming can be realized, cable enquiry and searching can also be realized without the need of changing the line operation mode and cutting off power, and the installation operation is simple, so that the power cable monitoring device is suitable for monitoring various shielded and armored cables.
Description
Technical field
The utility model relates to power cable monitoring device.
Background technology
Along with the raising that urban beautification and electric power require, the number of cables that is used for electric energy transmitting grows with each passing day, and cable line spreads all over streets and lanes.In cable trough, 3～5 at least on the cable that same hole is laid, 20～30 at most, in addition more.
Power cable can be divided into core and protective layer two large divisions on structure, the core that is positioned at the innermost layer is used for electric energy transmitting, is rolled in the outer protective layer of core and has sandwich construction, realizes functions such as shielding, insulation, anti-outside destroy respectively.In protective layer, but the material that is used for preventing the armor of outside destroy and being used for the screen layer of electromagnetic screen has electric conductivity.This paper abbreviates the conductive part in the cable protective layer as conductive layer.At middle pressure and above defeated, power distribution network, because voltage is higher, theft live electric cable regular meeting causes thief's injures and deaths, and this class thievery is very few in the past to be taken place, so cable is not installed safety-protection system.
In the past, it mainly was the copper material that aims at lead that the robber steals power circuit, had occurred the stolen incident of a lot of 10kV power cable insulation protective layers in this year.Because cable laying is hidden, and the anti-system of prison is not set, thus the cable protective layer stolen do not cause power failure and short circuit accident be difficult for be found.Some places, the thief has caused system short-circuit when stealing the protection of 10kV cable insulation, causes thief's injures and deaths and power failure; After the cable protective layer that has is stolen, though temporarily do not take place to have a power failure or personnel casualty accidents, but the cable insulation degree of protection declines to a great extent, switching overvoltage, lightning surge, harmonic wave superpotential, personnel trample, damaged by rats, all will trigger short circuit, a certain phase short circuit blast, often cause many feeder lines short circuit simultaneously of laying in one ditch, cause large-area power-cuts, this shows, the robber has buried the serious potential safety hazard in many places to electric system.Because the cable after many protective layers are stolen is imbedded in underground, power department does not have the security situation of special monitoring of equipment cable so far, the protective layer that can't learn power cable is destroyed, thereby can not in time adopt remedial measures, make electric system and peripheral personnel and environmentAL safety be subjected to serious threat.
In addition, cable insulation is stolen brings enormous economic loss to the country and people.With regard to the accident that has taken place, only repair again that the expense of cable has tens0000, the hundreds of thousands that has, have in addition cross ten million yuan, and accident allows user and power department suffer to have a power failure the loss that brings to be unable to estimate.The cable that is operated in precarious position just day by day increases, and sets up the cable safety-protection system, and protection electric power system safety is very urgent.
In the prior art, the content of not monitoring about power cable.The cable that retrieves is differentiated and the troubleshooting device is directly voltage or electric current directly to be added on core or the steel armor to carry out basically, needs to have a power failure and carries out, and is not suitable as monitoring usefulness.
In addition, in the cable corridor of many cable layings in one ditch,, do not cause short circuit but need to have a power failure when keeping in repair, confirm that this cable is which root cable of which bar feeder line if certain root cable section is damaged, could interruption maintenance.The method of searching with existing cable detecting device is that all cables through this highway section are had a power failure respectively, will be at the cable end place wherein two-phase and connecing respectively, at one end connect signal generator then and send detection signal, other end ground connection is detected detection signal at the cable bad place and is differentiated this cable.Workload is big like this, and will repeatedly have a power failure and just can finish, and is consuming time bothersome, and the science and technology that is difficult to satisfy current high speed development is to the requirement of safe, reliable, the high-quality of electrical network.
The utility model content
The utility model is intended to provide a kind of power cable monitoring device of can be easy to use, being applicable to real-time monitoring power cable state.
The utility model provides power cable monitoring device, it is characterized in that, comprise transmitter and receiver, transmitter transmitting supervisory signal makes in the conductive layer of tested cable protective layer and produces induction electromotive force, receiver detects the induced current that is produced by induction electromotive force and exports testing result in described conductive layer loop, transmitter has the transmission transformer that is enclosed within on the power cable, send winding as the elementary winding that sends transformer, tested cable is as sending Secondary winding of transformer, when sending the winding indirect current, can produce induction electromotive force in the conductive layer of power cable protective layer.
Power cable monitoring device of the present utility model, its transmitter transmitting supervisory signal make the conductive layer in this protective layer produce induction electromotive force.Because during normal the use, conductive layer in the protective layer constitutes the loop the feeder ear and the receiving end difference ground connection of power cable with the earth, satisfies the condition that induced current produces, so above-mentioned induction electromotive force produces induced current in above-mentioned conductive layer loop, receiver just can receive this induced current.The conductive layer loop of the impedance in the core loop that constitutes together with two ends bus and transformer because of core in the power cable in the protective layer, induced current on the conductive layer loop of the induced current that monitor signal produces on the core loop in the protective layer is so can not influence the testing result of receiver.Transmitter of the present utility model adopts electromagnetic coupled, realizes that high-low pressure isolates, and installs and during monitoring, all need not to change the method for operation of circuit, also needn't have a power failure, and operate simple and easyly, so is applicable to the state of real-time monitoring power cable.
Described power cable monitoring device, its receiver has the receiving transformer that is enclosed within on the tested cable, and tested cable is connected to the secondary winding of the reception winding of work current surveying machine as receiving transformer as the elementary winding of receiving transformer.
Receiver adopts the mode of transformer, realizes the high-low pressure isolation, has improved security, is applicable to real-time monitoring; The transformer adopting closed magnetic core can improve signal to noise ratio (S/N ratio), suppresses undesired signal, thereby reaches higher precision.
Described power cable monitoring device, its transmitter has the Current Negative Three-Point Capacitance unit, and transmitter is according to the intensity of current feedback signal adjustment transmitting supervisory signal, and the induced current intensity that produces in the feasible under normal circumstances described conductive layer loop is setting value.
Because the cable of different model specification has different resistance value Z
L, stake resistance also is not quite similar, so for different cables, resulting impedance Z
AlwaysBe a variable, and vary within wide limits, the induced current variation range is also very big like this, differentiates for measurement and has brought difficulty.The access of Current Negative Three-Point Capacitance unit allows transmitter adjust the intensity of transmitting supervisory signal according to current feedback signal, make that the induced current intensity that produces in the under normal circumstances described conductive layer loop is setting value, be applicable to all lengths, specification cable monitoring, inquire about, search.
Described power cable monitoring device, the monitor signal frequency is more than or equal to 5kHz, less than 50kHz.
Because the frequency of operation of power cable is 50Hz, so should avoiding the frequency of operation of power cable, the monitor signal frequency of the utility model power cable monitoring device disturbs, to be advisable more than or equal to 5kHz; Simultaneously, because, may make and all receive monitor signal on the many cables when monitor signal frequency during near radio frequency, influence the testing result of this machine and other power cable, the monitor signal frequency is unsuitable too high again, so the monitor signal frequency is unsuitable too high, to be advisable less than 50kHz.
Description of drawings
Fig. 1 is the block scheme of power cable monitoring device.
Fig. 2 is the fundamental diagram that sends transformer.
Fig. 3 is the fundamental diagram of receiving transformer.
Fig. 4 is the stolen automatic alarm system synoptic diagram of cable monitoring.
Fig. 5 adopts the movably synoptic diagram of transmitter inquiry cable.
Fig. 6 adopts receiver movably to search the synoptic diagram of cable.
Embodiment
Power cable monitoring device of the present utility model such as Fig. 1, when the monitoring instruction of input is " 0 ", first photoelectrical coupler is output as " 0 ", two PWM controllers quit work, the primary voltage that sends transformer is " 0 ", promptly do not have signal to be added on the tested cable, power cable monitoring device quits work.
When the monitoring instruction of input was " 1 ", first photoelectrical coupler was output as " 1 ", two PWM controllers work, the conduction angle Ψ of PWM-1 controller control DC1/DC2 transducer, supply voltage U
DC2Be 12V, by vibration, conversion boosts, rectification, obtains DC voltage U
DC2, different conduction angle Ψ can corresponding different output voltage U
DC2Value.
The PWM-2 controller is used to control the DC2/AC transducer, and the ac square wave frequency is 20kHz, and the amplitude of AC is exactly U
DC2Value, AC is added to the voltage that sends the primary winding, as shown in Figure 2, secondary is tested cable (circle), its induced electromotive force E
AC1Be directly proportional with AC voltage.
Accompanying drawing 2 is that its secondary winding is that the conductive layer of tested cable produces electromotive force E after describing transmission transformer input AC signal
AC1Under normal circumstances form induced current i
H
The armor of power cable and screen layer are metallic conductors, the impedance Z of the conductive layer in the protective layer of whole cable (this paper is hereinafter to be referred as conductive layer)
LNot quite, the two ends of conductive layer are cable terminal place ground connection, and its stake resistance R1, R2 all are not more than 4 ohm.The resulting impedance in this loop is Z
Always=R1+R2+Z
LThe induced electromotive force E that on cable, (is equivalent to a circle coil)
AC1Effect produces induced current i down
H=E
AC1/ Z
AlwaysIf the cable insulation protective layer is stolen, conductive layer disconnects, Z
AlwaysBe infinitely great, i
H≈ 0.
Under normal circumstances, the cable of different model specification has different Z
LValue, stake resistance also is not quite similar, so for different cables, resulting impedance Z
AlwaysBe a variable, and vary within wide limits, the induced current variation range is also very big like this, differentiates for measurement and has brought difficulty.Adopt the Current Negative Three-Point Capacitance unit just to solve this problem.The signal that will be directly proportional with cable induced current takes out, and through amplifying, regulates the size of conduction angle Ψ by the PWM-1 controller and controls U
DC2With the size of AC voltage, thereby realize i under the normal condition
HThe purpose that in scope by a small margin, changes.Stolen when cable, the stolen conductive layer of cable insulation protective layer disconnects Z
Always≈ ∞, then i
H≈ 0.
The receiving transformer of receiver is enclosed within (as shown in Figure 3) on the tested cable, and tested cable has only a circle as the elementary winding of receiving transformer, is connected to the secondary winding of the reception winding of work current surveying machine as receiving transformer.When tested cable flows through induced current i
HThe time, the receiving transformer magnetic flux that can produce alternation unshakable in one's determination, secondary winding produces induced electromotive force E
22, through frequency-selecting, amplification, detection, obtain DC voltage Uf, the induced current i that Uf and tested cable conduction layer produce
HBe directly proportional,, also be equivalent to the induced current size by level indicator indication Uf size.
Ugd adopts voltage divider to make reference voltage from the constant voltage that power supply takes off, from the negative terminal input comparator.When Uf＞Ugd, comparer output high level by second photoelectrical coupler, sends normal signal and gives the note machine or directly export normal signal and show.Otherwise, as Ugd＞Uf (induced current i
HLess than setting value) time, the comparer output low level sends to the cable fault signal by second photoelectrical coupler and note machine the place of setting.Photoelectrical coupler wherein is to be convenient to data information transmission, realizes computer controlled automatic and warning automatically.
Judge whether the cable protective layer is stolen.Concrete enforcement is as follows:
After the note machine is received and patrolled and examined signal, just send signal and allow the transmitter work 10 seconds of No. 1 cable, No. 1 cable is monitored, if its receiver all feeds back " normally " signal during this period, then No. 1 transmitter quits work, and makes the transmitter work 10 seconds of No. 2 cables, and No. 2 cables are monitored; If its receiver all feeds back " normally " signal, then No. 2 transmitters quit work, and make the transmitter work 10 seconds of No. 3 cables, No. 3 cables are monitored, so itinerant monitor system.
If the n receiver sends " undesired " signal, send out signal stolen in order to reduce, and note is confidential again to the n transmitter, sends monitor signal continuously three times, still 10 seconds at every turn owing to disturbing to miss.If it is undesired all to report for three times, just send " stolen " information.
Synoptic diagram such as Fig. 4 of the cable automatic monitoring system that is made of the electric power power cable monitoring device, the power cable monitoring system mainly is made up of power cable monitoring device, computing machine, control and communication module (note machine or single-chip microcomputer and communication connection device).
One of power cable monitoring system shown in Figure 4 embodiment.
At first on the power cable of need monitoring power cable monitoring device being installed, in each switch room (station) the note machine being installed respectively again, also can be single-chip microcomputer and communication connection device, and connects Surveillance center.
Transmitter and receiver are by computing machine (or by note machine) control.Computing machine connects warning devices such as loudspeaker, display, wireless or wire communication module, and when receiver detected less than induction current, the computer control loudspeaker sent caution sound, or on display display abnormality information.Computing machine carries out wireless connections by the dispatching center in a wireless communication module and a distant place, and when receiver detected less than induction current, computing machine sent abnormal information to the dispatching center.
Surveillance center's computing machine sends instruction, carry out monitoring (also can start monitoring) with SMS notification note machine control power cable monitoring device with line traffic control or manual operation, monitoring device is monitored cable, and monitoring result is fed back to note machine (perhaps directly exporting the result).When monitoring device monitors abnormal conditions, note machine or single-chip microcomputer send alarm signal to Surveillance center, Surveillance center's computing machine is received the abnormal alarm signal, promptly report to the police automatically, and extract relevant cable information automatically, the link power information system shows the trend of unusual cable on geography information figure.When the monitoring device of the cable more than two sent alerting signal, the public corridor of above cable laying was exactly the highway section of thief's crime.The relevant personnel go to prevent and destroy, and arrest the suspect.
Press Fig. 5, as cable inquiry, send the cable request signal of 0.5Hz+20KHz with transmitter movably to cable this moment, the 20KHz signal arranged in promptly 1 second, and next second there is not signal, and the 20KHz signal is arranged next time again.The cable request signal sends to cable to be looked into by mobile transmitter, and power cable monitoring device receives the 0-1 signal of 0.5Hz.The note machine sends the cable that the XX of XX transformer station cable will be inquired about for the staff by 0-1 signal and the address code of information 0.5Hz.
Press Fig. 6,, make the transmitter of power cable monitoring device send the 1Hz+1KHz+20KHz signal continuously, use movably receiver received signal this moment as searching cable louding.By first order frequency-selecting 20KHz device, detect 1KHz, the 1KHz that the promotion loudspeaker send 1Hz intermittently rings, and judges cable louding with the voice signal size, and this removable receiver can adopt receiving transformer type receiver, also can adopt bar magnet type receiver.When bar magnet and cable axis totally one plane, when for example parallel or vertical, the signal minimum.When bar magnet vertical with cable axis, but not during copline, the signal maximum.With this principle, judge tested cable louding and can differentiate cable.
Claims (4)
1. power cable monitoring device, it is characterized in that, comprise transmitter and receiver, transmitter transmitting supervisory signal makes in the conductive layer of tested cable protective layer and produces induction electromotive force, receiver detects the induced current that is produced by induction electromotive force and exports testing result in described conductive layer loop, transmitter has the transmission transformer that is enclosed within on the power cable, sends winding as the elementary winding that sends transformer, and tested cable is as sending Secondary winding of transformer.
2. power cable monitoring device according to claim 1, it is characterized in that, described receiver has the receiving transformer that is enclosed within on the tested cable, and tested cable is connected to the secondary winding of the reception winding of work current surveying machine as receiving transformer as the elementary winding of receiving transformer.
3. according to the power cable monitoring device of claim 1, it is characterized in that, described transmitter has the Current Negative Three-Point Capacitance unit, transmitter is according to the intensity of current feedback signal adjustment transmitting supervisory signal, and the induced current intensity that produces in the feasible under normal circumstances described conductive layer loop is setting value.
4. according to the power cable monitoring device of claim 1, it is characterized in that the monitor signal frequency is more than or equal to 5kHz, less than 50kHz.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200618832U CN201166697Y (en) | 2007-12-21 | 2007-12-21 | Power cable monitoring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200618832U CN201166697Y (en) | 2007-12-21 | 2007-12-21 | Power cable monitoring device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201166697Y true CN201166697Y (en) | 2008-12-17 |
Family
ID=40192087
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2007200618832U Expired - Lifetime CN201166697Y (en) | 2007-12-21 | 2007-12-21 | Power cable monitoring device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201166697Y (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101196550B (en) * | 2007-12-21 | 2012-01-11 | 赵瑞琳 | Power cable monitoring device and method for monitoring power cable state using the same |
| CN105021858A (en) * | 2015-07-16 | 2015-11-04 | 国家电网公司 | Anti-electricity theft system |
| CN105339801A (en) * | 2013-07-02 | 2016-02-17 | 皇家飞利浦有限公司 | Problem detection in cable system with fuses |
| CN105911376A (en) * | 2016-04-07 | 2016-08-31 | 重庆勤智科技有限公司 | Active excitation type multi-frequency induced current cable identification method and device |
| CN109444600A (en) * | 2018-12-11 | 2019-03-08 | 国网河南省电力公司南阳供电公司 | Track instrument is sought in a kind of high frequency carrier injection type low-voltage circuit path |
-
2007
- 2007-12-21 CN CNU2007200618832U patent/CN201166697Y/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101196550B (en) * | 2007-12-21 | 2012-01-11 | 赵瑞琳 | Power cable monitoring device and method for monitoring power cable state using the same |
| CN105339801A (en) * | 2013-07-02 | 2016-02-17 | 皇家飞利浦有限公司 | Problem detection in cable system with fuses |
| CN105021858A (en) * | 2015-07-16 | 2015-11-04 | 国家电网公司 | Anti-electricity theft system |
| CN105021858B (en) * | 2015-07-16 | 2019-05-10 | 国家电网公司 | Antitheft electric system |
| CN105911376A (en) * | 2016-04-07 | 2016-08-31 | 重庆勤智科技有限公司 | Active excitation type multi-frequency induced current cable identification method and device |
| CN105911376B (en) * | 2016-04-07 | 2020-06-12 | 重庆勤智科技有限公司 | Active excitation type multi-frequency induced current cable identification method and device |
| CN109444600A (en) * | 2018-12-11 | 2019-03-08 | 国网河南省电力公司南阳供电公司 | Track instrument is sought in a kind of high frequency carrier injection type low-voltage circuit path |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20081217 Effective date of abandoning: 20071221 |